One-step preparation, microstructure and properties of WRe/TZM gradient material for X-ray tube of CT scanner

Abstract

WRe/TZM gradient material was successfully fabricated simultaneously by spark plasma sintering technique with the gradient die to achieve the one-step bonding. The gradient sintering behavior and the effect of the sintering parameters on microstructure and mechanical properties of WRe/TZM joint were investigated. The results showed that the powders of WRe and TZM alloys could be densified and bonded simultaneously using gradient die to construct different sintering temperatures, and the relative densities of gradient material with WRe and TZM alloys were over 98%. The optimal joint with no pores and cracks was obtained at T = 1600 °C, t = 8 min and P = 30 MPa, under which the joint has the highest shear strength of 279.92 MPa. The Berkovich hardness of interface was mainly affected by the grain size and the solid solution of W and Mo. The resistance to creep at interface was between WRe alloy and TZM alloy. The joint exhibited excellent thermal diffusivity of 44.86 mm2/s. The WRe/TZM gradient material with excellent properties indicates this process is a promising technique route for fabricate the anode target for X-ray tube of CT scanner.

Keywords

• WRe alloy
• TZM alloy
• Gradient material
• Spark plasma sintering
• Microstructure
• Nanoindentation